Field of the Invention
The present invention relates to an organic light-emitting diode (OLED) display device and, more particularly, to an OLED display device for providing a signal to control a transistor and a power voltage to drive an OLED by using one signal line.
Discussion of the Related Art
An organic light-emitting diode (OLED) display device is a self-emissive device for emitting light from an organic emission layer using recombination of electrons and holes and is regarded as a next-generation display device due to a high brightness level, a low driving voltage, and an ultra-thin size thereof.
Each of a plurality of pixels included in the OLED display device includes an OLED including an organic emission layer between an anode and a cathode and a pixel driving circuit for independently driving the OLED. The pixel driving circuit largely includes a switching thin film transistor (TFT), a capacitor, and a driving TFT. The switching TFT charges a voltage corresponding to a data voltage in the capacitor in response to a scan pulse (or gate pulse), and the driving TFT controls the amount of light emitted from the OLED, by controlling the amount of current applied to the OLED depending on the magnitude of the voltage charged in the capacitor. The amount of light emitted from the OLED is proportional to the current applied from the driving TFT.
However, the OLED display device according to a related art has various problems because a plurality of signal lines are provided on a display panel and thus spaces for OLEDs and pixel driving circuits are restricted. Specifically, various signal lines such as data lines, reference lines, power lines, and gate lines are provided on the display panel to cross one another, and regions for the OLEDs and pixel driving circuits are defined at locations where the signal lines cross one another.
Since a plurality of signal lines are provided on a display panel and thus spaces for OLEDs and pixel driving circuits are restricted, the OLED display device according to the related art has problems such as a reduction in aperture ratio, and a reduction in brightness level due to the reduction in aperture ratio.
Also, since a large amount of current is applied to increase the brightness and to compensate for the small aperture ratio, large power consumption or rapid deterioration of the OLEDs is caused.
In addition, the OLEDs may not be provided in a necessary size due to the lack of space, a sufficient amount of current may not be applied to the OLEDs due to the restriction in size, and thus a desired brightness level may not be achieved.